- adder - a person who adds numbers
--1 is a kind of calculator, reckoner, figurer, estimator, computer
- adder - a machine that adds numbers
--2 is a kind of calculator, calculating machine
Derived forms: verb add5, verb add4 - adder, common viper, Vipera berus - small terrestrial viper common in northern Eurasia
--3 is a kind of viper
--3 is a member of Vipera, genus Vipera - adder - a machine that adds numbers